To date, there are no empirically validated treatments of good quality for adolescents showing suicidal ideation and behavior. Risk factors for suicide are impulsive and non-suicidal self-injurious behavior, depression, conduct disorders and child abuse. Behind this background, we tested the main hypothesis of our study: that Mode Deactivation Therapy (MDT) is an effective treatment for these patients. MDT has been developed by Jack Apsche especially for the individual or family-based residential or outpatient treatment of adolescents with problem behaviors and complex comorbid conditions. The efficacy of MDT was measured by a pre- and post-treatment comparison with the aid of standardized instruments (CBCL, STAXI-2, BDI-II, and SIQ) and compared to the results of a treatment-as-usual (TAU) control group. The comparative results confirmed that MDT is a consistent effective treatment for suicidal adolescents that appear to outperform other therapy approaches. (PsycINFO Database Record (c) 2019 APA, all rights reserved)